Recent mobile terminals are featured with various functions attractive to users. For example, the mobile terminals are provided with a voice telephony function, a still and/or motion picture capturing function, a broadcast playback function, an Internet access function, and/or the like.
More recently, the mobile terminals are featured with wireless video transmission function for transmitting video data (including audio data) to another terminal (e.g., a smart TV) through a wireless communication channel (e.g., Wi-Fi, Bluetooth, and cellular communication channels). According to the related art, Wi-Fi Display (WFD), Wireless Display (WiDi), and Miracast™ are representative wireless video transmission technologies.
If the wireless video transmission function is activated, the portable terminal transmits the video data to a recipient terminal through a Transmission Control Protocol (TCP) or a User Datagram Protocol (UDP) channel. Typically, the portable terminal uses the UDP channel for video data transmission to secure high data rate rather than reliability or the TCP channel to guarantee reliability. For example, the portable terminal may transmit the home screen data through the UDP channel and the motion picture data through the TCP channel.
In order to avoid fluctuation over a wireless communication channel and to guarantee seamless video quality, the transmission end should buffer the multimedia data, with a predetermined buffer size (or time). Likewise, the recipient terminal has a buffer with a predetermined buffer size to buffer the received multimedia data for seamless playback. Such buffering causes latency between the transmission terminal and the recipient terminal. Such time latency is prolonged when the radio communication environment between the transmission and recipient terminals deteriorates.
Meanwhile, the recipient terminal initializes the buffer when the transmission mode is changed. It is a shortcoming of the technology according to the related art that the multimedia data buffered in the reception buffer is discarded when the transmission mode is changed. This means that the multimedia data transmitted by the transmission terminal are lost as a result of the initialization of the reception buffer. For example, if the video playback of the recipient terminal stops in the state that the transmission terminal is transmitting the multimedia data to the recipient terminal, the transmission terminal changes the transmission mode from the TCP mode to UDP mode. At this time, the recipient terminal initializes the buffer to discard the buffered video data. As discussed above, one of the drawbacks of the video data transmission method and the video streaming method according to the related art is that the video data transmitted by the transmission terminal are not played entirely to the user.
The above information is presented as background information only to assist with an understanding of the present disclosure. No determination has been made, and no assertion is made, as to whether any of the above might be applicable as prior art with regard to the present disclosure.